Safety Divers for Deep Dives - What Do They Do?

[Rick Inman]

Sounds like they did a nice job for you guys.

PS---post a bit about your dive.

20 mins at 250'. 15/55 backgas. Three deco bottles: 120', 70', 20'. Total dive time was 85 mins. Vis at depth was 50' to 80', and the water temp was 39 degrees at depth and 62 degrees at 20'.

This was a wall dive. The wall starts at 50 to 70' and drops straight down to... well, we were hanging at 250' looking down far past 300' and the wall just keeps going. The structure of the wall is beautiful, with sections of flat, straight wall that stretches up out of view above and below us, and areas of cracks and canyons and pinnacles, and boulders that are (some) as big as a house that look like some giant kid tossed them there.

Last time we made this dive, we found a ford truck at 200' that had a license plate from the 70's (about 100 yards out the mountain face on shore is a small road). Shallow, there are tons of big small mouth bass that visit us, and swim up inquisitively. There's a water pipe running parallel to shore at 20' that we swim easily along during the last stops.

We had some minor imperfections in the dive, but the stops, gas switches and bottle switches went off without a hitch and exactly on the planned time.

And fortunately, the support divers were a pleasant addition, and not a necessity.

BTW, the three support divers said they really enjoyed the dive and can't wait to go with us again. Nice...

 

[texdiveguy]

20 mins at 250'. 15/55 backgas. Three deco bottles: 120', 70', 20'. Total dive time was 85 mins. Vis at depth was 50' to 80', and the water temp was 39 degrees at depth and 62 degrees at 20'.

This was a wall dive. The wall starts at 50 to 70' and drops straight down to... well, we were hanging at 250' looking down far past 300' and the wall just keeps going. The structure of the wall is beautiful, with sections of flat, straight wall that stretches up out of view above and below us, and areas of cracks and canyons and pinnacles, and boulders that are (some) as big as a house that look like some giant kid tossed them there.

Last time we made this dive, we found a ford truck at 200' that had a license plate from the 70's (about 100 yards out the mountain face on shore is a small road). Shallow, there are tons of big small mouth bass that visit us, and swim up inquisitively. There's a water pipe running parallel to shore at 20' that we swim easily along during the last stops.

We had some minor imperfections in the dive, but the stops, gas switches and bottle switches went off without a hitch and exactly on the planned time.

And fortunately, the support divers were a pleasant addition, and not a necessity.

BTW, the three support divers said they really enjoyed the dive and can't wait to go with us again. Nice...

Really sounds like a super dive...what great vis....nothing much better than a wall. Glad to hear you had some comfy water up top to pass the time in. What were you using on the 120' switch?

 

[Rick Inman]

Really sounds like a super dive...what great vis....nothing much better than a wall. Glad to hear you had some comfy water up top to pass the time in. What were you using on the 120' switch?

35/25

I love fall for diving around here. Top water temps are still up and air temps are nice and cool so we don't overheat on the surface. In just a few short months, the water will be cold throughout all depths, and I won't do anymore long hangs. One hour max total dive time for me when the water is below 45 degrees. A DS flood could make for a really bad day if you still owe an hour. Gee... I guess I'll have to make the 3 hour drive to Puget Sound for warmer waters.

 

[texdiveguy]

35/25

I love fall for diving around here. Top water temps are still up and air temps are nice and cool so we don't overheat on the surface. In just a few short months, the water will be cold throughout all depths, and I won't do anymore long hangs. One hour max total dive time for me when the water is below 45 degrees. ADS flood could make for a really bad day if you still owe an hour. Gee... I guess I'll have to make the 3 hour drive to Puget Sound for warmer waters.

I hear you on the cold hangs....dang makes me chill just thinking of them.....thats funny about going to PS for warmer water!! The 35/25 is a good gas at that level.....anyone task load with some photos??

 

[Rick Inman]

...anyone task load with some photos??

My buddy Allen has been bringing his video camera lately and handing it off to me. We left it at home on this dive, and I'll tell you, not having to deal with that thing during the dive makes just doing the dive seem so task-free.

This last summer, my trimix instructor did a class, and I carried his video camera for 10 dives 160' to 250'. We were staging shots - sending me down to 200' alone and shooting up the wall as the class descended. Then me leaving early so I could shoot the switches.

I really learned to respect technical videographers.

No camera yesterday. Very nice!

 

[texdiveguy]

My buddy Allen has been bringing his video camera lately and handing it off to me. We left it at home on this dive, and I'll tell you, not having to deal with that thing during the dive makes just doing the dive seem so task-free.

This last summer, my trimix instructor did a class, and I carried his video camera for 10 dives 160' to 250'. We were staging shots - sending me down to 200' alone and shooting up the wall as the class descended. Then me leaving early so I could shoot the switches.

I really learned to respect technical videographers.

No camera yesterday. Very nice!

Cool....lets you more enjoy the dive...and thats what you want anyways!! Dang I respect you folks that can use a camera underwater....I am dangerous with one on land!

 

[diver12345]

You may have immensely more experience at this than I. As, this has been our first summer utilizing a Safety Diver. So take my thoughts with several grains of salt.

First, you're assuming that the first gas switch won't be happening any deeper than 70'. I understand that would be the standard GUE gas to combine with oxygen. However, a team may be making their first switch at a depth greater than 70'. Either due to the use of a third gas, or because they've chosen a gas other than 50%.

With regard to "going back up and telling the boat everyone is o.k." We prefer our safety diver(s) stay with the team. There is little you can do for us while you're commuting to and from the boat. The boat doesn't necassaryily need to know everyone's o.k. We need to know we have support with us if needed. If there is some support that we are going to be in need of but that the safety diver can't provide or that will require time to coordinate, then head to the boat with such info.

After the 20' switch. We're not as concerned with unloading our deeper gas bottle as we are ridding our selves of cameras, specimens, tools and the like. We really have no use for the later and would like to get them on the boat with out any hurry. But, we might have a use for that gas and it's generally less in the way than the other stuff. And now visible from the surface, we're more comfortable with the idea of the safety diver commuting to and fro. Plus, it's a shorter trip and poses less yo-yoing for the safety diver who may be doing a second dive, or who may have completed an earlier dive.

We like the idea of having the additional O2 cylinder in the water, not on the boat. It can't help us on the boat. But, if one of ours has a issue and there's a second immediately available there is no reason to worry about altering schedules.

Backgas. We feel it's important that the safety diver can descend to any depth that they might see an issue at. And for the sake of simplicity in gas sharing, and contingency plans that it is important that their gas be one of the teams gases. If your teams first swith is at 70' and they are using 32 as a bachgas then it would make sense to use the same. However if the first switch is at 130' then it might be a good idea to have the same gas as the team in your backgas tanks. One scenario that we've discussed, is the possibility of the safety diver seeing the team ascending on a gas share. There should be no reason the safety diver can't descend and potentially provide much needed additional gas(of the same type).

This doesn't mean you have to be breathing your backgas. Here we are in agreement with regard to the benefits of 32%. The difference lies in that we're carrying it in al80 stage.

Just our reasoning for adopting a different set of protocols than your own.

Yes was referring to dives with the first gas switch at 70ft. On dives were the switch takes place at 120 then you would meet them there and have the correct mix in your tanks.

Going back to the surface to let the boat know things are good, just keeps the boat in the loop. I see them as a part of the team. The time that you are out of touch with the team should be minamal. 2 min ascent and a quick OK signal then down you go. No more than 4 min seperation. I do see the merit in having them stay with you as well. I don't see toxing an issue at this stop.

We keep the 02 on the boat so the safety diver has less bottles to deal with. It maybe a small al40 but it still limits your mobility. Then when @ the 20ft I take anything the team doesnt need. Bottles,scooters,bags,or cameras.

Lets say your team is doing a 250 dive with the first switch at 120. Would you want 15/55 in your back gas? I would say 25/25. You get a benifit of the higher 02 and helium. Less potential to go into deco at that depth. If you have the vis to see your team at depth(which we dont have anything of the sort here in the northwest) asending on a gas share I would assume that the team has calculated a rock bottom and has the gas to make it to the first switch. It may be inconviente for them but if the skill was not there to do a gas share and hold relatively short deep stops then some practice is in store for the team. I would not leave the team untill each member has at least one redundant gas supply. IE the OOA diver Has his 120 bottle and their 70 bottle @ 70 ft to use.

The most imporatant thing here is that the team is on the same page at all times. I only dive with the same 5 people. We are all trimix 2 cert. We take turns safety diving for eachother. Comunication is easy underwater for us. If we charter a boat it is with someone we trust and just happens to also be a trimix diver. Reducing the risk as a whole equals safe diving for all.

 

[texdiveguy]

diver12345...........

What are you saying here???
"Lets say your team is doing a 250 dive with the first switch at 120. Would you want 15/55 in your back gas? I would say 25/25."

 

[Rick Inman]

diver12345...........

What are you saying here???
"Lets say your team is doing a 250 dive with the first switch at 120. Would you want 15/55 in your back gas? I would say 25/25."

He must mean 25/25 in your deco bottle. 25/25 at 250' is a po2 of 2.12 and an end of 177'.


Or something...

 

[rainman_02]

I'm thinking he's saying the safety diver should be on 25/25 not 15/55.

Since 120 is their "max depth."